Pumpless liquid cooling system

ABSTRACT

A pumpless liquid cooling system for removing heat from heat-generating components or systems comprises a heat absorbing portion or cold plate, a heat dissipating portion or heat exchanger and at least one driving device. The heat absorbing portion and the heat dissipating portion are of unitary construction as a sealed container with working fluid inside. The driving device and the heat dissipating portion is co-axially aligned and attached or fastened together. The heat absorbing portion is configured to have at least one thermal contact surface and a plurality of liquid passage within. The heat dissipating portion is configured to have a heat-dissipating body with plurality of external fins and an internal cylindrical liquid passage communicating with those of the heat absorbing portion and having a running fitting impeller driven by the driving device via magnetic forces to circulate the liquid in the heat transfer loop. Meanwhile the driving device moves the cool air through the fins of the heat dissipating portion to reject the heat absorbed by the heat absorbing portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is associated to the Provisional patent application filed on Aug. 10, 2007, Application No. 60/964,345

STATEMENT REGARDING FEDERAL SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

FIELD OF THE INVENTION

This invention generally relates to the art of liquid cooling system, and in particular, to a pumpless liquid cooling system having the unitary construction of heat-absorbing portion and heat-dissipating portion with a pumpless liquid circulating device for removing heat from heat-generating components or systems.

BACKGROUND OF THE INVENTION

Liquid cooling apparatus or liquid cooling systems of a wide variety of designs have been, to some extends, employed to dissipate heat generated by electronic components on printed wiring or circuit boards, video cards, computer CPUs, LED displays and solar energy systems, etc. to prevent the electronic components or systems from failure due to over heating. More than ever before, today's electronic products and energy systems are reducing the size and cost, dramatically increasing power and speed, so the traditional air cooling can no longer meets the needs. Liquid cooling is inevitable and has thus been increasingly used in electronic and solar energy industries to cool those electronic packages, components and systems. Therefore the liquid cooling apparatus or liquid cooling systems used in electronic packaging, video, gaming and solar energy systems, etc. must be smaller in size, lower in cost, easier installation, higher efficiency, heat transfer rate and reliability to meet the technology trends.

Generally, a liquid cooling system comprises a heat-absorbing member or cold plate, a heat-dissipating member or heat exchanger and a liquid circulating device or pump. These individual components are connected together in series so as to form a heat transfer loop. In practice, the heat-absorbing member is maintained in thermal contact with a heat-generating component (e.g. a GPU, a CPU or a FET, and Diode, etc) for absorbing the heat generated by the component. A liquid cooling system employs a working fluid (coolant or water) circulating through the heat transfer loop so as to continuously bring the thermal energy absorbed by the heat-absorbing member to the heat-dissipating member where the heat is rejected. The pump is used to circulate the coolant or water from cooling area to heating area then back to cooling area and so on.

Traditionally, in a liquid cooling system, the heat-absorbing member or cold plate, the heat-dissipating member or heat exchanger and the driving device or pump are connected together generally by a plurality of connecting tubes and fittings so as to form the heat transfer loop. Therefore, the liquid cooling system has a big volume and occupies more room in an electronic system and can not achieve the compact and dense packaging, and is not adapted to a small, portable electronic product. Furthermore, the liquid cooling system has a pump, connecting tubes and fittings with a plurality of connections, which is prone to lead to leakage of the liquid, low reliability of system and a high cost of the product. Moreover, due to the tubes, fittings, connections the pump and the separation of heat-absorbing member and the heat-dissipating member, the Installation and removal of the liquid cooling system in/from the electronic system is a burdensome and time-consuming work.

Also, in a typical liquid cooling system, a pump must always be employed in order to circulating the liquid/coolant between heating and cooling area. It is well known that pump generates noises and vibrations, and has lower reliability, higher cost and maintenance. This creates the obstacle for building the quiet, portable, reliable and compact electronic and solar products with affordable price.

In order to improve construction of the liquid cooling system, reduce the connecting tubes and fittings, more and more liquid cooling systems are constructed as “integrated system”. An example of the latter may be seen in U.S. Pat. Nos. 7,379,301 and 7,013,959, titled as “Integrated Liquid Cooling System”. These integrated liquid cooling systems are good examples for reduce connections in liquid cooling system assembly to improve reliability and reduce size. However, none of them have been able to eliminate the pump in the so-called “Integrated Liquid Cooling System”, which has a big impact on the reliability, cost, size and acoustic noise for a liquid cooling system.

Accordingly, what is needed is the art of a smaller size, higher reliability, lower cost, easier assembly/disassembly liquid cooling system which overcomes the foregoing disadvantages and is ready for attaching heat generating components or devices thereon without the need of using pump, connecting tubes and fittings to realize the true compact and portable product design.

SUMMARY OF THE INVENTION

A pumpless liquid cooling system in accordance with an embodiment of the present invention for removing heat from heat-generating components or systems comprises a heat absorbing portion or cold plate, a heat dissipating portion or heat exchanger and at least one driving device. The heat absorbing portion is configured to have at least one thermal interface surface and a plurality of tubes/channels running inside its body for liquid to pass through. The heat dissipating portion is configured to have a heat dissipating body with an internal cylindrical liquid passage, inlet and outlet communicating to the heat absorbing portion and a plurality of fins extended from or attached thereto its external surface. There is, at least, one impeller running-fitting inside the cylindrical liquid passage and located at one end of the heat dissipating body for the purpose to circulating liquid, and there is an orifice at the other end of the heat dissipating body for the purpose of filling-up liquid and being sealed with a plug thenafter. The impeller is configured to have a shaft with radical spiral vanes and a circular magnet or magnetic disc permanently attached coaxially at one end and having a supporting bearing at the other end. The heat absorbing portion and heat dissipating portion is of unitary construction as a sealed container with working fluid inside. The driving device comprises a frame or stator configured to have the round or rectangular shape with plurality of mounting apertures and a rotor configured to have the cylindrical shape with circular magnet or magnetic disc coaxially attached at the end and a plurality of vanes radically attached or born. The driving device is attached or fastened on the heat dissipating portion and coaxially located with the impeller inside. The impeller driven by the driving device via the magnetic field forces from the pair of magnetic discs circulates liquid between the heat absorbing portion and the heat dissipating portion, and the vanes of driving device, meanwhile, below the air through fins on the heat dissipating portion to reject heat carried by liquid or coolant from the heat absorbing portion. The sealed container and pumpless liquid circulating of this cooling system makes it possible for a liquid cooling system to be simple, cheap, quiet, efficient, reliable, compact and portable.

A pumpless liquid cooling system according to the present invention avoids using the high cost and low reliability pump to circulating the liquid inside the cooling system. The pumpless liquid cooling system of the present invention also avoids the requirement for separate attachments, such as sealing rings, tubes and fittings. In such all-in-one solution pumpless liquid cooling system, it greatly reduces the assembly time and costs.

It is a further object of the present invention to provide a pumpless liquid cooling system with high heat transfer rate which can be further improved by using high thermal conductive liquid, such as nano-fluid, without changing the physical size of the cooling system and having the possibility for a product to be made smaller without the risk of overheating.

It is yet a further object of the present invention to provide a pumpless liquid cooling system that the unitary construction of the heat absorbing portion and heat dissipating portion makes a sealed container for working liquid and connectionless between driving portion in dry area and driven portion in wet area be realized for power transfer. Therefore the troublesome of mechanical seal is avoided.

It is yet a further object of the present invention to provide a pumpless liquid cooling system that can be used for cooling variety products, such as power electronics, computers, gaming, displays and solar energy system, etc.

The foregoing has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B illustrate the embodiments of the prior arts of integrated liquid cooling systems.

FIGS. 2A and 2B are the perspective drawings of an embodiment of the present invention.

FIGS. 3A, 3B and 3C are two perspective and one principle views with half section cut of an embodiment of a heat absorbing portion.

FIGS. 4A, 4B and 4C are the perspective, exploded and partially section views of an embodiment of a heat dissipating portion.

FIGS. 5A, 5B and 5C are the perspective and section views of an embodiment of the heat dissipating body. FIG. 5E is a principle view of an embodiment of the impeller.

FIG. 5D is a perspective view of an embodiment of the supporting bearing.

FIGS. 6A and 6B are the perspective views of an embodiment of the driving device.

FIGS. 7A and 7B are the perspective drawings illustrating how the pumpless liquid cooling system is assembled together.

FIGS. 8A and 8B are the perspective drawings illustrating the pumpless cooling system is in use with heat generating components. FIGS. 8C and 8D are the principle drawings illustrating the cooling mechanism of the present invention—pumpless liquid cooling system.

DETAILED DESCRIPTIONS OF THE INVENTION

Referring initially to FIGS. 1A and 1B, illustrated are examples of prior art integrated liquid cooling systems 800, 900. The prior art integrated liquid cooling system 800 illustrated in FIG. 1A has a heat absorbing unit 4 containing coolant therein and a heat dissipating unit 2 having a liquid circulating module in communicating with heat absorbing unit 4 via two pipes 100 and 200. The heat generating component 6 is in contact with heat absorbing unit 4. Heat dissipating unit 2 having fan and a plurality of fins (not shown here) to reject heat absorbed by heat absorbing unit 4 and carried by the coolant circulated by a pump (not shown here). Apparently this integrated liquid cooling system has the disadvantages of: 1) having pipes or tubes and fitting for the connections; 2) lack of compact solid construction since the heat absorbing unit and the heat dissipating unit are separated and connected with tubes; 3) having a pump with higher cost and acoustic noise.

FIG. 1B illustrates another prior art integrated liquid cooling system 900. This integrated liquid cooling system has a compact design by eliminating the pipes or tubes, it comprises a base 10, a pump 20 mounted in the base and a heat-dissipating member 30 communicating with pump 20 and coupled with base 10. The bottom surface of the bottom plate 214 contacts heat generating component for absorbing heat. The heat will be rejected in the heat-dissipating member 30 via a plurality fin 301, a plurality of heat-dissipating conduits 304 and a pair of opposite fluid tanks 302, 303. Apparently this integrated liquid cooling system has the disadvantages of: 1) having a pump with higher cost and acoustic noise; 2) many parts counts make the system complicated; 3) no build-in cooling fan or blower for heat-dissipating unit.

FIGS. 2A and 2B are the perspective views of a pumpless liquid cooling system constructed according to a preferred embodiment of the present invention. In FIGS. 2A and 2B, a pumpless liquid cooling system 100 comprises a heat dissipating portion 160, a heat absorbing portion 120 and a driving device 140. The unitary construction of heat absorbing portion 120 and heat dissipating portion 160 makes a sealed container for working fluid. Heat absorbing portion 120 configured to have at least one thermal interface surface 180 for electronic component(s) to be attached thereto or contacted thereon. Heat dissipating portion 160 configured to reject heat absorbed from heat absorbing portion 120 and carried by liquid or coolant circulated inside. Driving device 140 configured to provide power for circulating the liquid (not shown here) therein and to move cool air through heat dissipating portion 160 for heat transfer. All the rotating members in the cooling system 100 are coaxially aligned with axis 0-0.

FIGS. 3A and 3B are the perspective views of, and FIG. 3C is the top view with half section of the heat absorbing portion 120, which comprises a body or base 124 with at least one thermal interface surface 180, an inlet 126, an outlet 128, a plurality of fins 122 attached or machined or born inside body 124 to form a plurality of liquid passages or channels 123. Inlet 126 and outlet 128 can be any shape as long as it facilitates liquid flows. Heat absorbing portion 120 is preferably constructed of inexpensive and better thermal conductive material, such as aluminum or copper, and fabricated by casting, machining, brazing, bonding together or the like. Heat absorbing portion 120 can even be made of good thermal conductive plastic or composite material.

FIGS. 4A, 4B and 4C are the perspective and exploded and section views of heat dissipating portion 160 according the present invention, showing that heat dissipating portion 160 is an assembly of several members, the relationship between them and how to assemble them together. Heat dissipating portion 160 comprises a heat dissipating body 162, an impeller 170, an end cap 110, maybe a support bearing 190 and a plug 200. Support bearing 190 is sliding into the mating apertures of 162 with non-transitional fit. Impeller 170 is sliding into its mating apertures of 162 with running fit. End cap 110 mate with the mating apertures of 162 to effect the sealing of liquid therein. End cap 110 may be manufactured using the same material as that of heat dissipating body 162, and be bounded, welded or brazed onto heat dissipating body 162. Plug 200 mates with the mating apertures of 162 to effect the sealing of liquid therein, preferred detachable like threads engagement. Plug 200 can be made of the same material as or different material from that of the heat dissipating body 162. End cap 110, impeller 170, support bearing 190, plug 200 and heat dissipating body 162 are in co-axially aligned with axis 0-0.

FIGS. 5A, 5B and 5C are the perspective and section views of an embodiment of the heat dissipating body 162. FIG. 5D is a principle view of an embodiment of the impeller 170 and FIG. 5E is a perspective view of an embodiment of the supporting bearing 190. The heat dissipating body 162 is configured to have a plurality of fins 164 extended from or attached to its outside body to increase the surface areas for better heat transfer, a plurality of apertures 163 to receive fasteners or other attachments, an orifice 168, a cylindrical liquid passage 167 with axis 169, an inlet 165 and an outlet 166. Heat dissipating body 162 is preferably constructed of non-ferrous, inexpensive and better thermal conductive materials, such as aluminum or copper, and fabricated by extrusion, casting, machining and the like, and the fins 164 is preferably constructed of inexpensive and better thermal conductive materials, such as aluminum or copper as well and then extended from or brazed or bonded. The impeller 170 comprises a shaft 186 with axis 187 and spiral blade 184 permanently attached or born radically and a magnetic disc 182 permanently attached at one end coaxially. Shaft 186 and blade 184 are preferably constructed as one piece and of inexpensive materials, such as aluminum, plastics or composite, fabricated by inexpensive means, such as casting, molding. The supporting bearing 190 is configured to have cylinder shape with an axis 199, a plurality of webs 194 for structural purpose, an outside ring 196 which will non-transitionally fit into the liquid passage 167 of heat dissipating body 162, an inside ring 198 into which shaft 186 of impeller 170 will fit and a plurality of voids 192 for liquid to flow through. The supporting bearing 190 is preferably constructed of inexpensive materials, such as aluminum or plastics, fabricated by inexpensive means, such as casting, molding.

FIGS. 6A and 6B are the perspective view of driving device 140 constructed according to a preferred embodiment of the present invention. The driving device 140 comprises a rotor 142 having axis 148 and a frame or stator 144 having a plurality of mounting apertures 150 and electrical wire 146 connected to a motor (not shown) inside of frame 144, driving rotor 142. Rotor 142 is configured to have a plurality of vanes 154 radically attached or born and a magnetic disc 152 coaxially attached. Frame 144 is configured to have the functions of supporting rotor 142 with motor and being fastened to heat dissipating portion 160. Rotor 142 and frame 144 may be made from non-ferrous metal or plastics, with inexpensive manufacturing means, such as stamping or molding or casting.

FIGS. 7A and 7B are the perspective views showing how the cooling system 100 is assembled together. The operations have the following steps:

(1). Assemble heat dissipating portion 160 together with heat absorbing portion 120 by bonding or brazing or vacuum brazing or the like. Align outlet 166 of heat dissipating body 162 with that of inlet 126 of heat absorbing portion 120. Inlet 167 of heat dissipating body 162 shall also be aligned with that of inlet 128 of heat absorbing portion 120.

(2). Fill up the liquid or coolant (not shown here) into the voids inside of the cooling system 100,

(3). Assemble plug 200 into orifice 168 of heat dissipating body 162 to effect the seal the liquid or coolant. At this point, the unitary construction of the heat absorbing portion and the heat dissipating portion becomes a sealed container with working fluid inside.

(4) Assemble driving device 140 onto the heat dissipating portion 160 using mounting apertures 150 on frame 144 and receiving apertures 163 on heat dissipating body 162 by fastening or other means. Axis 187 of impeller 170 shall be co-axial with axis 148 of driving device 140, divided by end cap 10. There is no physical connection between the driver and receiver.

OPERATIONS

In an operation of using this invention, one uses the cooling system 100 in a normal manner. As shown in FIGS. 8A and 8B show whole cooling system assembly 400 can be placed in different orientations to meet the heat generating component mounting and system design requirements. FIGS. 8A, 8B, 8C and 8D also show the electronic components 300 and 350 in contact with the thermal interface surface 180 of the cooling system 100, The step by step operation procedures are as following:

1). Attach the heat generating components 300 and 350 onto the cooling system 100 by snapping, clipping, fastening or bonding, etc. to make a cooling system assembly 400, then mount cooling system assembly 400 onto a printed circuit or wiring board (not shown here) and then make the components 300 and 350 in good contact with the thermal interface surface 180 of the cooling system 100. When heat-generating components 300 and 350 being powered, each will dissipate “Q” watts power and generate heat which is absorbed by the heat absorbing portion 120.

2). Power on the driving device 140, then the rotor 142 with magnetic disc 152 of driving device 140 will rotate with a speed RPM. Magnetic disc 152 of driving device 140 and magnetic disc 182 of impeller 170 are engaged with magnetic attraction, the magnetic field forces will drive the impeller 170 inside the heat dissipating portion 160 rotating with the same speed RPM (if no slip).

3). When impeller 170 rotating and acting like a feed-screw, its vanes 184 will push the working fluid (not shown) inside the heat dissipating portion 160 forward and therefore circulate the fluid inside the cooling system 100. The fluid pick-ups the heat (+Q) in the areas where the heat generating components are located and carries the heat (+Q) to heat dissipating portion 160.

4). Meanwhile, the vanes 154 on rotor 142 of driving device 140 move the air with rate of cubic feet per minute (CFM) through the fins 164 of the heat dissipating portion 160 to reject the heat (−Q) carried by the fluid circulating inside.

Obviously the present invention provides the cooling system with advantages as listed below:

1). High heat transfer rate

2). Ease of installation and removal

3). Cost effective

4). Compact Design

5). Minimum maintenance required

6). Higher reliability and lower acoustic noise without using a pump.

7). Multiple applications 

1. A pumpless liquid cooling system for removing heat from heat-generating components or systems comprising: (a) a heat absorbing portion; (b) a heat dissipating portion; and (c) at least one driving device; said heat absorbing portion and said heat dissipating portion being of unitary construction as a sealed container with working fluid inside; said heat dissipating portion configured to have liquid circulating mechanism internally and heat rejection capabilities externally; said heat absorbing portion and said heat dissipating portion having liquid passages internally and being connected to form heat transfer loop; said driving device and said heat dissipating portion being co-axially aligned and attached or fastened together.
 2. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 1 wherein said heat absorbing portion having a base or body configured to have at least one thermal interface surface, a plurality of liquid channels running inside for liquid passing through, an inlet and an outlet for liquid in and out;
 3. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 2 wherein said liquid channel may be built as micro-channel or milli-channel for maximum liquid contact areas and heat transfer rate.
 4. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 1 wherein said heat dissipating portion comprising a heat dissipating body, an impeller, an end cap, maybe a support bearing and a plug.
 5. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 4 wherein said heat dissipating body having extended external surface area or fins and internal cylindrical liquid passage, an inlet, an outlet and an orifice; said external surface area or fins for heat rejection with air passing through naturally or convectively; said inlet, said outlet and said liquid passage being in serial connection; said orifice being used for filling-up liquid.
 6. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 4 wherein said impeller comprising a shaft having an axis, a magnetic disc attaching to said shaft co-axially at one end of said shaft; a plurality of vanes attached or extended to said shaft radically.
 7. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 6 wherein said shaft with said vanes attached or extended may be a feed screw, so said impeller basically being a feed-screw with modifications.
 8. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 4 wherein said supporting bearing configured to have internal and external ring and a plurality of structural webs.
 9. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 4 wherein said heat dissipating body, said impeller, said end cap, said support bearing and said plug being assembled in co-axial relation; said impeller and said cylindrical liquid passage being running fit; said external ring of said supporting bearing and said cylindrical liquid passage being non-transitional fit; said internal ring of said supporting bearing and said shaft of said impeller being running fit; said end cap covering the open end of said cylindrical liquid passage after said impeller being assembled; said plug being plugged into said orifice after liquid being filled up.
 10. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 1 wherein said driving device comprising a frame and a rotor; said frame configured to have structure and a plurality mounting apertures; said rotor configured to have a shaft having a plurality vanes attached on or extended from radically and a magnetic disc attached on its end co-axially driven by a motor.
 11. A pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 10 wherein said driving device may an alter item of a commercially available axial fan.
 12. A heat pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 1 wherein said driving device and said heat dissipating portion being assembled together in the relationship so that said magnetic disc of said rotor and said magnetic disc of said impeller being co-axial and face-to-face divided by said end cap.
 13. A heat pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 1 wherein said heat dissipating portion and said heat absorbing portion being unitary construction in the relationship so that said internal cylindrical liquid passage, said inlet, said outlet and said liquid channel being in serial connection to form liquid circulating heat transfer loop.
 14. A heat pumpless liquid cooling system for removing heat from heat-generating components or system as recited in claim 1 wherein said internal cylindrical liquid passage, said inlet, said outlet and said liquid channel being internal voids for liquid volume.
 15. A pumpless liquid cooling system for removing heat from heat-generating components or systems comprising: (a) a heat absorbing portion; (b) a heat dissipating portion; (c) at least one driving device; and (e) means for liquid circulating without using a pump said heat absorbing portion and said heat dissipating portion being of unitary construction as a sealed container with working fluid inside; said heat dissipating portion configured to have liquid circulating mechanism internally and heat rejection capabilities externally; said heat absorbing portion and said heat dissipating portion having liquid passages internally and being connected to form heat transfer loop; said driving device and said heat dissipating portion being co-axially aligned and attached or fastened together. said means for liquid circulating without using a pump being, instead, using said magnetic field force to transfer torques from said driving device to said impeller instead; said torques rotating said impeller exerting pressure on liquid so as to circulate liquid in said heat transfer loop.
 16. A pumpless liquid cooling system for removing heat from heat-generating components or systems as recited in claim 15 wherein said magnetic field force being from the pair of circular magnets on said rotor of said diving device and on said impeller in said heat dissipating portion.
 17. A pumpless liquid cooling system for removing heat from heat-generating components or systems as recited in claim 16 wherein said pair of circular magnets being separated by said end cap without direct contact.
 18. A pumpless liquid cooling system for removing heat from heat-generating components or systems comprising: (a) a heat absorbing portion; (b) a heat dissipating portion; (c) at least one driving device; and (d) means of physical connectionless between the driver and receiver said heat absorbing portion and said heat dissipating portion being of unitary construction as a sealed container with working fluid inside; said heat dissipating portion configured to have liquid circulating mechanism internally and heat rejection capabilities externally; said heat absorbing portion and said heat dissipating portion having liquid passages internally and being connected to form heat transfer loop; said driving device and said heat dissipating portion being co-axially aligned and attached or fastened together. said means of physical connectionless between the driver and the receiver being of no physical direct contact between driving portion and impeller of the heat dissipating portion.
 19. A pumpless liquid cooling system for removing heat from heat-generating components or systems as recited in claim 18 wherein said no direct contact between driving portion and liquid circulating impeller being realized by magnetic field force to transfer power from the driver to the receiver. 